Heatable media lines of this type and methods for the production thereof are known from the prior art. In vehicles in particular, a series of media lines are provided for conveying mostly fluid media. These media lines are susceptible to freezing at low temperatures, for which reason a heating system is provided. Line connectors are used for connecting at least two media pipelines or for the connector connection of a media pipeline to a desired assembly. Often such media as tend to freeze even at still quite high environmental temperatures, owing to a relatively high freezing point, are conveyed through the media pipelines, as a result of which the functionality, for example, of a vehicle may be impaired or even disturbed considerably. This is particularly apparent in the case of water lines for windscreen-washing systems, just as in the case of media lines, through which an aqueous carbamide solution flows as a medium that is used as an NOx reaction additive for diesel engines with so-called SCR catalytic converters.
EP 1 985 908 A1 discloses a line connector for media lines, which consists of a connector piece having a terminal section for terminal connection to the media line or to an assembly and having a transition section, which bounds the terminal section and has a flow duct. Electrical heating means are provided in an arrangement that at least partially encloses the flow duct, at least in the region of the transition section. The electrical heating means that are thus arranged in the transition section, that is, outside the terminal section, act to prevent freezing of the medium in question inside the connection piece or to rectify it by thawing of the frozen medium. The heating wire surrounds the connector piece in a wound, coil-like manner on the outside, at least one further coil winding being arranged in the inner region in the region of the flow duct, so that an induction is provided in the inner coil winding to produce heat when a current flows through the outer heating wire. The media line consists of an inner pipeline having a heating conductor arranged on the circumference, pipeline and heating conductor being enclosed by an outer sheath such as a corrugated tube. Line connectors are attached to both ends of the media line. An adhesive tape is wound around the heating conductor arranged on the pipeline, which is thereby fixed to the pipeline, before the corrugated tube is joined on. Alternatively, it is proposed that a varnish or adhesive layer be provided for fixing. The heating wires of the line connectors and the heating line of the pipeline are electrically connected to each other, in each case the heating wire of one of the line connectors being electrically series-connected to one of the winding wires of the heating line surrounding the pipeline and the terminal ends of the two series circuits being routed outwards at the two line connectors, where a connection to a voltage supply or a further connection is provided. Alternatively it is disclosed that the heating wires of the line connectors and of the windings surrounding the pipeline, as an electrical series circuit of all the heating wires, are provided with only one outer line terminal.
If a plurality of heating elements is routed along a media line and line connectors connected to the end of the latter, it can result in an excessively high heating power being produced, in particular at the line connectors. Heating conductors are usually adapted to the relevant media line and the power requirement thereof in terms of the strand selection and pitch etc. If the strand or strands or heating elements on the media line and the line connector are identical, the power input at the line connector is produced to a particular extent depending on the line length. In this case, the problem arises, in particular in the case of short lines, that too much power is coupled in, or also if heating filaments are used. A line connector only offers a few possibilities of varying the fastening of the heating conductors, since winding and fastening, that is, the distribution of the heating conductors on the line connectors, the number of windings, which is at least one or two, the positioning of a crimp connection, which is arranged in a housing surrounding the line connector, usually take place relatively uniformly for cost reasons. Even a possible fastening structure, for example a rib structure, on the outside of the line connector for fastening the heating conductors is usually formed identically in most line connectors. For short or very short lines of in particular less than one metre, the provision of a heating filament can be sensible. It would therefore be desirable to provide a measure that permits in particular the end line connectors of a heatable media line to be loaded with a lower heating power.
The present invention is therefore based on the object of creating an assembled heatable media line and a method for the production thereof, with which it is possible to achieve optimal heating power in relation to the medium conducted through the heatable media line having end line connectors, in particular in the region of the at least one end line connector.